The United States spends half a trillion dollars a year on scientific research — more than any other nation on Earth — but China has pulled into second place, with the European Union third and Japan a distant fourth.

China is on track to surpass the United States by the end of this year, according to the National Science Board. In 2016, annual scientific publications from China outnumbered those from the United States for the first time.

“There seems to be a sea change in how people are talking about Chinese science,” said Alanna Krolikowski, a Chinese science expert at Missouri University of Science and Technology. Foreign observers, many of whom were once condescending, now “are rather in awe at what the Chinese policies have accomplished.”

Italian scientists have been citing themselves more often since a controversial law came into effect in 2010 demanding academics meet productivity thresholds to gain promotion. Economic and managerial engineering showed the greatest leap in self-citations from 2010 to 2014 of the four fields examined.